Gas storage and dispensing system with monolithic carbon adsorbent

ABSTRACT

A pyrolyzed monolith carbon physical adsorbent that is characterized by at least one of the following characteristics: (a) a fill density measured for arsine gas at 25° C. and pressure of 650 torr that is greater than 400 grams arsine per liter of adsorbent; (b) at least 30% of overall porosity of the adsorbent including slit-shaped pores having a size in a range of from about 0.3 to about 0.72 nanometer, and at least 20% of the overall porosity including micropores of diameter&lt;2 nanometers; and (c) having a bulk density of from about 0.80 to about 2.0 grams per cubic centimeter, preferably from 0.9 to 2.0 grams per cubic centimeter.

CROSS-REFERENCE TO RELATED APPLICATIONS

This is a continuation under 35 USC 120 of U.S. patent application Ser.No. 13/,216,207 filed Aug. 23, 2011 in the name of J. Donald Carruthersfor “GAS STORAGE AND DISPENSING SYSTEM WITH MONOLITHIC CARBONADSORBENT,” which in turn is a continuation under 35 USC 120 of U.S.patent application Ser. No. 12/392,077 filed Feb. 24, 2009 in the nameof J. Donald Carruthers for “GAS STORAGE AND DISPENSING SYSTEM WITHMONOLITHIC CARBON ADSORBENT,” issued Aug. 23, 2011 as U.S. Pat. No.8,002,880, which in turn is a continuation-in-part under 35 USC 120 ofU.S. patent application Ser. No. 11/103,224 filed Apr. 11, 2005 in thename of J. Donald Carruthers for “GAS STORAGE AND DISPENSING SYSTEM WITHMONOLITHIC CARBON ADSORBENT,” issued Feb. 24, 2009 as U.S. Pat. No.7,494,530, which in turn is a is a continuation-in-part under 35 USC 120of U.S. patent application Ser. No. 10/767,901 filed Jan. 29, 2004 inthe name of J. Donald Carruthers for “GAS STORAGE AND DISPENSING SYSTEMWITH MONOLITHIC CARBON ADSORBENT,” issued Sep. 6, 2005 as U.S. Pat. No.6,939,394, which in turn is a continuation under 35 USC 120 of U.S.patent application Ser. No. 10/315,635 filed Dec. 10, 2002 in the nameof J. Donald Carruthers for “GAS STORAGE AND DISPENSING SYSTEM WITHMONOLITHIC CARBON ADSORBENT,” issued Jun. 1, 2004 as U.S. Pat. No.6,743,278.

FIELD OF THE INVENTION

The present invention relates generally to gas storage and dispensingsystems, and particularly to systems of such type utilizing a monolithiccarbon sorbent as a gas storage medium.

DESCRIPTION OF THE RELATED ART

The physical adsorbent-based gas storage and dispensing system disclosedin Tom et al. U.S. Pat. No. 5,518,528 has revolutionized thetransportation, supply and use of hazardous gases in the semiconductorindustry. The system includes a vessel holding a physical adsorbentmedium such as molecular sieve or activated carbon, having sorptiveaffinity for the gas that is to be stored in and selectively dispensedfrom the vessel. The gas is held in the vessel in an adsorbed state onthe sorbent medium at reduced pressure relative to a corresponding empty(of sorbent) vessel holding an equivalent amount of gas in the “free”(unadsorbed) state.

By such reduced pressure storage, the safety of the gas storage anddispensing operation is substantially improved, since any leakage willresult in a very low rate of egress of gas into the ambient environment,relative to a conventional high pressure gas storage cylinder. Further,the low pressure operation of the adsorbent-based system is associatedwith a lower likelihood of such gas leakage events, since the reducedpressure reduces the stress and wear on system components such asvalves, flow controllers, couplings, joints, etc.

In such adsorbent-based gas storage and dispensing systems, the workingcapacity of the physical adsorbent medium is an operating constraint.The working capacity is the amount of gas that can be stored (“loaded”)on the sorbent medium and desorptively removed from such sorbent mediumfor use. The working capacity is a function of the storage pressure ofthe gas in the sorbent medium-containing gas storage vessel, and thedispensing condition of the desorbed gas (e.g., dispensing pressure ofthe desorbed gas, when pressure differential is used to effectdesorption, and temperature levels of respective storage and dispensingconditions, when thermal desorption of gas is used as the dispensingmodality), and the type and character of the sorbent medium itself(e.g., involving such parameters as sorbent media size, shape, porosity,pore size distribution, and tortuosity of interior pore passages).

The art is continually seeking improvement in working capacity of thephysical adsorbent-based gas storage and dispensing system.

SUMMARY OF THE INVENTION

The present invention relates to physical adsorbent-based gas storageand dispensing systems, and to an improved working capacity system ofsuch type.

In one aspect, the present invention relates to a fluid storage anddispensing apparatus, comprising a cylindrical fluid storage anddispensing vessel having an interior volume, wherein the interior volumecontains a physical adsorbent for sorptively retaining a fluid thereonand from which the fluid is desorbable for dispensing from the vessel,and a valve head coupled to the vessel for dispensing desorbed fluidfrom the vessel, wherein the physical adsorbent comprises a pyrolyzedmonolithic carbon physical adsorbent that is characterized by at leastone of the following characteristics:

-   -   (a) a fill density measured for arsine gas at 25° C. and        pressure of 650 torr that is greater than 400 grams arsine per        liter of adsorbent;    -   (b) at least 30% of overall porosity of said adsorbent        comprising slit-shaped pores having a size in a range of from        about 0.3 to about 0.72 nanometer, and at least 20% of the        overall porosity comprising micropores of diameter<2 nanometers;        and    -   (c) having a bulk density of from about 0.80 to about 2.0 grams        per cubic centimeter, preferably from 0.9 to 2.0 grams per cubic        centimeter.

In another aspect, the invention relates to a fluid storage anddispensing vessel having disposed therein a monolithic sorbent that ischaracterized by at least one of the following characteristics:

-   (a) a fill density measured for arsine gas at 25° C. and pressure of    650 torr that is greater than 400 grams arsine per liter of    adsorbent;-   (b) at least 30% of overall porosity of said adsorbent comprising    slit-shaped pores having a size in a range of from about 0.3 to    about 0.72 nanometer, and at least 20% of the overall porosity    comprising micropores of diameter<2 nanometers; and-   (c) a bulk density of from about 0.80 to about 2.0 grams per cubic    centimeter.

A further aspect of the invention relates to a method of making a gaspackage useful for storing and dispensing gas, comprising: providing acylindrical gas storage and dispensing vessel; disposing a physicaladsorbent in the vessel having sorptive affinity for said gas; andcoupling said vessel with a valve head containing an actuatable valve;wherein the physical adsorbent comprises a monolithic carbon physicaladsorbent that is characterized by at least one of the followingcharacteristics:

-   -   (a) a fill density measured for arsine gas at 25° C. and        pressure of 650 torr that is greater than 400 grams arsine per        liter of adsorbent;    -   (b) at least 30% of overall porosity of said adsorbent        comprising slit-shaped pores having a size in a range of from        about 0.3 to about 0.72 nanometer, and at least 20% of the        overall porosity comprising micropores of diameter<2 nanometers;        and    -   (c) a bulk density of from about 0.80 to about 2.0 grams per        cubic centimeter.

Another aspect of the invention relates to a method of packaging gas forsubsequent dispensing, said method comprising: providing a cylindricalgas storage and dispensing vessel having disposed therein a physicaladsorbent having sorptive affinity for said gas, said vessel beingcoupled with a valve head containing a valve that is actuatable for saidsubsequent dispensing; charging said gas to said vessel for adsorptionon said physical adsorbent; and sealing said vessel; wherein thephysical adsorbent comprises a monolithic carbon physical adsorbent thatis characterized by at least one of the following characteristics:

-   -   (a) a fill density measured for arsine gas at 25° C. and        pressure of 650 torr that is greater than 400 grams arsine per        liter of adsorbent;    -   (b) at least 30% of overall porosity of said adsorbent        comprising slit-shaped pores having a size in a range of from        about 0.3 to about 0.72 nanometer, and at least 20% of the        overall porosity comprising micropores of diameter<2 nanometers;        and    -   (c) a bulk density of from about 0.80 to about 2.0 grams per        cubic centimeter.

A still further aspect of the invention relates to a method of supplyinggas to a gas-utilizing process, said method comprising: providing a gaspackage including a cylindrical gas storage and dispensing vesselcontaining a physical adsorbent and gas adsorbed on said physicaladsorbent, and a valve head coupled to said vessel, said valve headincluding a valve that is actuable for gas dispensing; actuating theactuatable valve in said valve head for gas dispensing, desorbing gasfrom the physical adsorbent, and dispensing gas from the vessel to saidgas-utilizing process; wherein the physical adsorbent comprises amonolithic carbon physical adsorbent that is characterized by at leastone of the following characteristics:

-   -   (a) a fill density measured for arsine gas at 25° C. and        pressure of 650 torr that is greater than 400 grams arsine per        liter of adsorbent;    -   (b) at least 30% of overall porosity of said adsorbent        comprising slit-shaped pores having a size in a range of from        about 0.3 to about 0.72 nanometer, and at least 20% of the        overall porosity comprising micropores of diameter<2 nanometers;        and    -   (c) a bulk density of from about 0.80 to about 2.0 grams per        cubic centimeter.

Other aspects, features and embodiments of the present invention will bemore fully apparent from the ensuing disclosure and appended claims.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a graph of weight in grams of phosphine (PH₃) adsorbed perliter of carbon, as a function of pressure level, in torr, for a Kureha578-66-6 bead activated carbon (data points marked by solid diamondmarkers), a Takachiho ABF 14-03 particulate activated carbon (datapoints marked by solid square markers), and carbon formed frompolyvinylidene chloride polymer (Saran A, Dow Chemical Co.) (data pointsmarked by open triangular markers).

FIG. 2 is a graph of volume, in cubic centimeters, of arsine (AsH₃)adsorbed per liter of carbon, as a function of pressure level, in torr,for a Kureha 578-66-6 bead activated carbon (data points marked by soliddiamond markers) and carbon formed from polyvinylidene chloride polymer(Saran A, Dow Chemical Co.) (data points marked by open triangularmarkers).

FIG. 3 is a schematic representation of a storage and delivery systemutilizing a monolithic sorbent, according to one embodiment of theinvention.

FIG. 4 is a perspective view of a rectangular parallelepiped fluidstorage and dispensing vessel utilizing a monolithic sorbent, accordingto another embodiment of the present invention.

FIG. 5 is a graph of adsorbed weight, in grams, of boron trifluoride(BF₃) adsorbed per liter of carbon, as a function of pressure level, intorr, for a Kureha 578-66-6 bead activated carbon (data points marked bysolid diamond markers) and carbon formed from polyvinylidene chloridepolymer (Saran A, Dow Chemical Co.) (data points marked by solid squaremarkers).

FIG. 6 is an elevation view, in partial section, of a fluid storage anddispensing system utilizing a monolithic sorbent, according to a furtherembodiment of the invention.

FIG. 7 is an elevational view, in cross-section, of the top and bottomportions of the cylindrical fluid storage and dispensing system of FIG.6.

DETAILED DESCRIPTION OF THE INVENTION, AND PREFERRED EMBODIMENTS THEREOF

The present invention is based on the discovery that a physicaladsorbent-based fluid storage and dispensing apparatus may be fabricatedutilizing a fluid storage and dispensing vessel having a monolithiccarbon adsorbent material therein, with surprising and unexpectedadvantages as regards the nature and extent of sorption and desorptionof gas on the adsorbent, the packing density achievable for the physicalsorbent medium in the vessel, and the utility of the fluid storage anddispensing apparatus comprising such vessel for semiconductormanufacturing operations.

The present invention thus achieves a substantial advance in the artover adsorbent-based gas storage and dispensing systems of the typedescribed in Tom et al. U.S. Pat. No. 5,518,528 which heretofore haveused physical sorbent media in a finely divided form, such as aso-called bead activated carbon. In accordance with the presentinvention, the gas storage and dispensing system can be significantlyimproved in working capacity when the activated carbon is provided, notin a bead or particulate form, but rather in a monolithic form ofspecific character.

The level of improvement achievable by the use of a monolithic form ofactivated carbon, relative to the finely divided forms used in the priorart, is highly unexpected, and is even more surprisingly improved whenthe gas storage and dispensing vessel is of a shape conforming to theadsorbent monolith.

For example, when the vessel is of a preferred cube or other rectangularparallelepiped shape, consistent with the disclosure of U.S. patentapplication Ser. No. 10/314,777 filed Dec. 9, 2002 in the names ofDennis Brestovansky, et al., for “Rectangular Parallelepiped FluidStorage and Dispensing System,” issued on Jan. 31, 2006 as U.S. Pat. No.6,991,671, the use of a conformably shaped monolith can increase theworking capacity of the physical adsorbent-based gas storage anddispensing system by at least 85% relative to a prior art system using agas storage cylinder of the same “footprint” and vessel interior volume,filled with bead activated carbon.

By way of background to explanation of the unanticipated advantages ofthe preferred packaging of the monolithic physical adsorbent of theinvention in a rectangular parallelepiped conformation vessel in thephysical adsorbent-based fluid storage and dispensing apparatus, itwould on initial consideration appear to be highly disadvantageous toemploy a rectangular parallelepiped conformation for aphysical-adsorbent-based fluid storage and dispensing system, since: (i)a rectangular parallelepiped vessel has six faces, and twelve weld-linesrequired for fabrication if each face of the vessel is a separate piece(by contrast, a cylindrical vessel may be formed without seams fromtubular rolled steel stock); (ii) consistent with (i), the fabricationcost of a rectangular conformation vessel would be expected to besubstantially higher than for a corresponding cylindrical vessel; (iii)a rectangular parallelepiped conformation involves “sharp” corners atthe juncture of adjacent perpendicularly oriented walls that offer thepotential of forming voids at the line of juncture, wherein the sorbentbed would not “pack” against the corner, relative to a correspondingcylindrical geometry vessel (which is free of such corners, and insteadis a minimum cross-sectional area shape circumscribing the bed ofphysical sorbent material in the interior volume of the vessel); and(iv) the intersection of two perpendicular walls with one anotherproduces a joint that is susceptible to rupture by pressure or forcedirected thereon, relative to a “seamless” cylindrical vessel.

It has been determined, however, that the rectangular parallelepipedconformation results in a vessel which does have less tightly packedsorbent bed regions adjacent the seams at the intersection of adjacentwalls, but that rather than being a disadvantage, such lower densitysorbent bed regions are in fact advantageous as higher gas flowconductance pathways for interstitial desorbed or unadsorbed gas to flowout of the bulk volume of the sorbent bed.

Further, precisely because the cylindrical vessel is a minimumcross-sectional area conformation, with a minimum circumferential extentof circumscribing wall area, the amount of sorbent that is “presented”to the wall in the cylindrical vessel is maximized. Considering theconverse, the peripheral extent of the wall that bounds (is adjacent to)the sorbent bed in cross-section is much greater in the rectangularparallelepiped conformation than in the cylindrical vessel. Therectangular parallelepiped conformation thereby enables higher volumeegress of gas from the vessel than from a correspondingly sizedcylindrical vessel, because the wall surface bounding the sorbent bed isnon-adsorbing in character, and there is proportionally more of it inthe rectangular conformation vessel, at the outer margins of the sorbentbed, than there is in the cylindrical vessel. As a result, the desorbedgas at the wall regions is less readsorbed subsequent to its initialdesorptive release from the sorbent medium than desorbed gas in theinterior portions of the sorbent bed.

For these reasons, the rectangular parallelepiped vessel conformationhas particular utility for holding the monolithic form of the physicaladsorbent of the present invention.

As used herein, “monolithic” means that the sorbent medium is in aunitary or block-like form, e.g., in the form of blocks, bricks, discs,boules, etc., in contradistinction to conventional finely divided formssuch as beads, particles, granules, pellets, and the like, which aregenerally utilized in the form of a bed comprising a multiplicity ofsuch beads, particles, granules, pellets, etc. Thus, in the bed form ofmultiple finely divided physical adsorbent elements, the void volume ofthe active sorbent is in major part interstitial, or inter-particle, incharacter, varying according to the dimensions, shape and packingdensity of the sorbent particles. By contrast, in a monolithic form, thevoid volume of the active sorbent is in form of porosity intrinsic tothe sorbent material and voids that may have been formed in the bulksorbent body during its processing.

The present invention in one aspect relates to a fluid storage anddispensing apparatus, comprising a fluid storage and dispensing vesselhaving an interior volume, wherein the interior volume contains aphysical adsorbent sorptively retaining a fluid thereon and from whichthe fluid is desorbable for dispensing from the vessel, and a dispensingassembly coupled to the vessel for dispensing desorbed fluid from thevessel, wherein the physical adsorbent comprises a monolithic carbonphysical adsorbent. The pyrolyzed monolith carbon physical adsorbent inthe vessel is characterized by at least one of the followingcharacteristics:

-   -   (a) a fill density measured for arsine gas at 25° C. and        pressure of 650 torr that is greater than 400 grams arsine per        liter of adsorbent;    -   (b) at least 30% of overall porosity of said adsorbent        comprising slit-shaped pores having a size in a range of from        about 0.3 to about 0.72 nanometer, and at least 20% of the        overall porosity comprising micropores of diameter<2 nanometers;        and    -   (c) having been formed by pyrolysis and optional activation, at        temperature(s) below 1000° C., having a bulk density of from        about 0.80 to about 2.0 grams per cubic centimeter, preferably        from 0.9 to 2.0 grams per cubic centimeter, more preferably from        1 to 1.3 grams per cubic centimeter, and most preferably from        1.05 to 1.25 grams per cubic centimeter.

The monolithic adsorbent can be in the form of a single monolithicadsorbent article, or a multiplicity of monolithic adsorbent articles.The adsorbent can be suitably shaped to conform to the interior volumeof the vessel in which it is disposed, and preferably occupies at least60% of the interior volume of the vessel, e.g., from 75 to 95% of suchinterior volume. While the invention is discussed more fully hereinafterin respect of containment of the monolithic adsorbent in the preferredrectangular parallelepiped shaped vessel, it will be appreciated thatthe invention is not thus limited, and that other vessel shapes andconformations can be utilized, e.g., cylindrical-shaped vessels,barrel-shaped vessels, frustoconical-shaped vessels, etc.

The monolithic adsorbent can be formed as the pyrolysis product of anorganic resin, and more generally can be formed from any suitablepyrolyzable material, such as for example polyvinylidene chloride,phenol-formaldehyde resins, polyfurfuryl alcohol, coconut shells, peanutshells, peach pits, olive stones, polyacrylonitrile, and polyacrylamide.The adsorbent can be formed in the fluid storage and dispensing vesselin which the fluid will be stored for subsequent dispensing, i.e., insitu, or the adsorbent can be formed and then introduced into the fluidstorage and dispensing vessel. In one embodiment, the adsorbent has atleast 20% of its porosity in pores with a diameter of less than 2nanometers.

The adsorbent can be provided in the fluid storage and dispensing vesselas a multiplicity of monolithic adsorbent articles that aggregatelyconstitute the adsorbent mass. In such multiple monolithic articlearrangement, each of the multiplicity of discrete monolithic adsorbentarticles can have a length that is between 0.3 and 1.0 times the heightof the interior volume of the vessel, and a cross-sectional area that isbetween 0.1 and 0.5 times the rectangular cross-sectional area of thevessel. Each of the multiplicity of discrete monolithic articles canhave a rectangular parallelepiped shape or alternatively a cylindricalor other suitable shape. In the interior volume of the fluid storage anddispensing vessel, the discrete monolithic articles can be laterallyand/or longitudinally abutted in surface contact with adjacentmonolithic members. In one embodiment, each of the multiplicity ofdiscrete monolithic articles has a length to cross-sectional dimensionratio, L/D, that is from about 2 to about 20, e.g., in a range of fromabout 4 to about 15, where L is the length or major axis dimension ofthe monolithic carbon sorbent article, and D is the transverse or minoraxis dimension. In another embodiment, the monolithic adsorbent articlecan have a disc shape, with a height to diameter ratio, H/D, that isfrom about 0.10 to about 0.80, more preferably from about 0.15 to about0.60, and most preferably from about 0.20 to about 0.50. In a particularembodiment, the disc-shaped monolithic adsorbent article can have aheight to diameter ratio, H/D, that is in a range of from about 0.2 toabout 0.3.

The fluid in the fluid storage and dispensing vessel that is sorptivelyretained on the adsorbent, and desorbed under suitable desorbingconditions for dispensing of fluid, can be fluid of any suitable type,e.g., fluid having utility in semiconductor manufacturing, such ashydrides, halides and organometallic gaseous reagents, e.g., silane,germane, arsine, phosphine, phosgene, diborane, germane, ammonia,stibine, hydrogen sulfide, hydrogen selenide, hydrogen telluride,nitrous oxide, hydrogen cyanide, ethylene oxide, deuterated hydrides,halide (chlorine, bromine, fluorine, and iodine) compounds, andorganometallic compounds.

The fluid in the vessel can be stored at any suitable atmospheric,sub-atmospheric or super-atmospheric pressure, e.g., pressure below 2500torr, such as in a range of from about 20 torr to about 1200, orpressure in a range of from about 20 torr to about 750 torr forsubatmospheric pressure supply of gases for ion implantation or othersubatmospheric pressure application.

The vessel holding the adsorbent having fluid adsorbed thereon can beformed of any suitable vessel material(s) of construction, such asmetals (e.g., steel, stainless steel, aluminum, copper, brass, bronze,and alloys thereof), glasses, ceramics, vitreous materials, polymers,and composite materials.

The vessel can be of any suitable shape and size, as appropriate to thespecific fluid storage and dispensing application. The vessel can, forexample, be of a rectangular parallelepiped shape, being of elongatevertically upstanding form, with a square cross-section, or the vesselcan be cylindrical with a circular cross-section, or in any otherappropriate shape, size and form.

In one embodiment, the invention utilizes a physical adsorbent ofmonolithic form in a rectangular parallelepiped vessel defining a closedinterior volume and having a port to which is coupled a gas dispensingassembly, for selective discharge of gas from the vessel. The sorbentmedium in the monolithic form of the present invention providessufficient capacity for sorptive retention of the sorbate gas in thedesired quantity, good desorptive release of gas under desorptionconditions, and good working capacity with good heels behavior (i.e.,high extent of desorption of initially adsorbed gas), and has anappropriate sorptive affinity for the gas of interest so that low gaspressure is maintained in the interior volume of the vessel duringstorage of gas therein.

The physical adsorbent in accordance with the present invention can beof any suitable monolithic form, e.g., in the form of blocks, bricks,boules or similar forms of the adsorbent material that are of a sizecommensurate with the fluid storage and dispensing vessel, so thatvessel contains one or a small number, e.g., less than 75, morepreferably less than 20, of the discrete monolithic articles. In afurther preferred aspect, the vessel contains no more than 8 suchdiscrete monolithic articles, even more preferably no more than foursuch articles, and most preferably the vessel contains a singlemonolithic physical adsorbent article.

The monolithic article(s) deployed in the fluid storage and dispensingvessel provide(s) an aggregate sorbent mass that is preferably conformedin size and shape to the interior volume of the fluid storage anddispensing vessel, so that the sorbent mass of the monolithic article(s)occupies at least 60% of the interior volume of the vessel, preferablyin a range of from about 75% to about 95% of the interior volume of suchvessel.

If provided as a single monolithic sorbent article, the sorbent mediummay for such purpose be formed in situ in the vessel, e.g., by pyrolysisof an organic resin that is in liquid or otherwise flowable form, withwhich the vessel is filled to a desired extent prior to pyrolysis ofsame in the vessel.

If alternatively provided in the form of multiple monolithic articles,each of such articles can be provided with a length that is between 0.3and 1.0 times the height of the interior volume of the vessel, and across-sectional area that is between 0.1 and 1.0 times the rectangularcross-sectional area of the vessel. Each monolithic member can have arectangular parallelepiped shape for maximizing the volumetric usage ofthe interior volume of the vessel when the vessel is of rectangularparallelepiped shape, wherein each of the monolithic members may belaterally and/or longitudinally abutted in surface contact with adjacentmonolithic members in the interior volume of the vessel. Alternatively,in some instances, it may be desirable for the sorbent monolithicmembers to be in the form of solid cylinders, with the respectivecylindrical members being loaded into the interior volume so as totangently abut one another along their facing side surface, and to atleast partially abut one another in face-to-face contact at theircircular cross-section end surfaces. In fluid storage and dispensingvessels of shapes other than cubic or other rectangular parallelepipedshapes, the monolithic sorbent article(s) may be correspondingly formedto conform to the shape of the interior volume of the vessel. Forexample, the fluid storage and dispensing vessel can be of cylindricalshape, with monolithic adsorbent articles therein comprising a verticalstack of disc-shaped bodies of adsorbent, each having diameterconforming it at its periphery to the shape of the vessel, in closeproximity to the facing inner wall surface of the vessel. In suchcylindrical-shaped vessel, or in vessels of other shapes, each of themonolithic bodies of adsorbent disposed in the vessel can have across-sectional area that is between 0.1 and 1.0 times the rectangularcross-sectional area of the vessel.

The level of improvement attendant the use of a monolithic form ofactivated carbon over finely divided particulate forms of the prior artis unexpected because physical adsorbent materials are generallyclassified in terms of their surface area available for sorptivelyretaining the working gas (adsorbate), and hence particulate forms withtheir high surface to volume ratio have been considered inherentlysuperior to bulk forms such as blocks and bricks (i.e., monolithicforms) having a lower apparent surface-to-volume ratio. Thus, one wouldexpect intuitively that monolithic forms of adsorbent would be lowefficiency forms, having a reduced sorptive capacity and workingcapacity.

It has been discovered, however, that a carbon monolith may be formedhaving a similar micropore volume as corresponding bead carbon, but witha substantially higher density, e.g., a density in a range of from about25% to about 80% higher than the compacted density of the correspondingbead carbon, and that such high density monolith when used in a physicaladsorbent-based gas storage and dispensing system provides a strikingimprovement in mass of gas adsorbed per unit volume of the sorbent incomparison to a bed of bead carbon.

Carbon monoliths useful in the broad practice of the present inventioninclude gross brick, block and ingot forms, as bulk forms, preferablyhaving three-dimensional (x, y, z) character wherein each of suchdimensions is greater than 1.5, and preferably greater than 2centimeters. For example, the carbon monolith may be in the form of amonolith briquette, as made from a polymeric char such as polyvinylidenechloride (PVDC) or other suitable polymer, having a high bulk density(measured with voids), e.g., on the order of from about 0.80 to about2.0 grams per cubic centimeter, preferably from 0.9 to 2.0 grams percubic centimeter, more preferably from 1 to 1.3 grams per cubiccentimeter, and most preferably from 1.05 to 1.25 grams per cubiccentimeter, with high working capacity (high microporosity and low heel)and pore tortuosity that is sufficiently low to ensure ready and rapidrate adsorption and desorption.

In one embodiment, the monolithic carbon sorbent of the inventionincludes a doping agent on the active carbon to minimize decompositionof the sorbate fluid during extended storage. Illustrative of dopingagents that can be usefully employed in the broad practice of theinvention are boric acid (H₃BO₃), sodium tetraborate (Na₂B₄O₇), sodiumsilicate (Na₂SiO₃) and disodium hydrogen phosphate (Na₂HPO₄).

The monolithic carbon adsorbent articles in another aspect can have alength to cross-sectional dimension ratio, L/D, that is from about 2 toabout 20, and more preferably from about 4 to about 15, where L is thelength or major axis dimension of the monolithic carbon sorbent article,and D is the transverse or minor axis dimension. In a specificembodiment, the monolithic carbon adsorbent is provided in the form of1″×1″ square cross-section PVDC char monolith briquettes, approximately6″ in height.

A preferred monolithic carbon adsorbent comprises pyrolysis products ofSaran A, Saran MC-10S or Saran XPR-1367-D-01452-050 PVDC homopolymers orcopolymers, as ultramicroporous carbons having a high proportion ofslit-shaped pores of small dimension, e.g., in a range of from about 0.3to about 0.75 nanometers.

When the monolithic carbon sorbent has pores with a diameter of lessthan about 2 nanometers, the monolithic carbon sorbent is able to adsorbgases, e.g., boron trifluoride, above their critical temperature to anextent that is proportional to the micropore volume of the sorbentmaterial. Preferred monolithic carbon sorbent materials for such purposehave a high proportion of pores, e.g., at least 50% of porosity, in thesmall micropore, e.g., ultramicropore, size range. This effect may beseen by reference to FIG. 5, which is a graph of weight in grams ofboron trifluoride (BF₃) adsorbed per liter of carbon, as a function ofpressure level, in torr, for (i) a Kureha bead activated carbon (datapoints marked by solid diamond markers) and (ii) carbon formed frompolyvinylidene chloride polymer (Saran A, Dow Chemical Co.) (data pointsmarked by solid square markers).

Although micropore volume is an important criterion for selecting carbonfor use in the monolithic carbon adsorbent systems of the invention, andmicropore volume is desirably maximized, gases stored in a fixed volumevessel are appropriately compared on a volume per liter of adsorbentbasis. The adsorbent packing density in such instance becomes extremelyimportant. To this end, the monolithic carbon eliminates void volume inthe fluid storage and dispensing vessel in which it is employed.

Void volume in the fluid storage and dispensing vessel in accordancewith the present invention, in a preferred embodiment, does not exceedabout 40% of the total interior volume of the vessel, and morepreferably is as low as possible. The packing density of the monolithiccarbon sorbent is desirably as high as possible, with maximum microporevolume on a volume per volume of adsorbent basis, and a high proportionof pore volume being in ultramicropores. The conformation of themicropores is also important, with the pores being desirably slit-shapedto provide high adsorption levels, but not so small so that the slitconformation interferes with ready gas release under desorptionconditions, e.g., desorption at pressure levels on the order of 40 torr.

During activation of carbon to form activated carbon, the pores arewidened at elevated temperature in the presence of a non-oxidizing gassuch as nitrogen, followed by exposure to an oxidizing gas such asoxygen or steam for a short duration, and then cooling in anon-oxidizing atmosphere. In such activation, the level of burn-off ofthe material is carefully controlled, since a high level of burn-offcauses widening of the pores, with an increase in micropore volume andconcomitant reduction of particle density.

The monolithic carbon adsorbent of the invention can be suitably formedin any suitable manner. In one embodiment, the monolithic carbon isformed from a polymeric material such as the polyvinylidene chloridepolymer commercially available from The Dow Chemical Company (Midland,Mich.) as Saran A or Saran MC-10S polymer, as pressure molded atsuitable pressure, e.g., a pressure in a range of from about 10kilopounds per square inch to about 20 kilopounds per square inch, andthen pyrolyzed in a nitrogen gas stream at a temperature of from about600° C. to about 900° C., e.g., on the order of about 700° C. Thisprocess produces a carbon sorbent material having a greatly increasedfill density (viz., the weight of gas adsorbed, e.g., in grams, perliter of carbon), as shown in the graphs of FIGS. 1 and 2.

The monolithic carbon adsorbent of the invention represents asignificant departure from the practice of the prior art, which hasutilized finely divided particles, such as bead activated carbon havinga particle diameter of 0.1-1.0 centimeter and more typically a particlediameter of 0.25-2.0 millimeters, or which, in the case of bulkmicroporous carbon materials (see Wojtowicz et al. U.S. PatentApplication Publication US2002/0020292 A1 published Feb. 21, 2002), hasutilized high temperature, e.g., >1000° C. and preferably >1100° C., toinduce high graphitization levels, in combination with activationinvolving repetitive chemisorption/desorption steps performed as many as76 times (see Quinn, et al. U.S. Pat. No. 5,071,820) to achieve suitablemicropore volume, surface area and micropore volume per unit volume ofcarbon adsorbent, a time-consuming and costly approach to obtaining asuitable sorbent material for high-pressure gas storage applications(Wojtowicz et al. U.S. Patent Application Publication US2002/0020292 A1discloses that optimal storage capacity for the sorbate gas requiresthat the gas “be introduced into the storage vessel at a pressure in therange of from about 500 psi to about 3500 psi,” page 2, paragraph[0013], last sentence).

In contrast to these prior art approaches, the monolithic carbon sorbentof the present invention is formed from a suitable polymeric material,e.g., a polymer selected from among polyvinylidene chloride,phenol-formaldehyde resins, polyfurfuryl alcohol, coconut shells, peanutshells, peach pits, olive stones, polyacrylonitrile, polyacrylamide,etc., that is pressure-moldable, e.g., at a molding pressure up to about20,000 psi or higher, to yield a pressure-molded “green resin” body thatis pyrolyzable at temperature below 1000° C., preferably not exceedingabout 900° C., e.g., in a range of from about 500° C. to about 900° C.,and more preferably in a range of from about 600° C. to about 900° C.,to yield a monolithic carbon material having a fill density of suitablyhigh value for the intended gas storage and dispensing application.Monolithic carbon sorbents useful in the practice of the presentinvention include those having a fill density measured for arsine gas at25° C. and a pressure of 650 torr that is in excess of 400 grams arsineper liter of carbon adsorbent, and preferably greater than 450 gramsarsine per liter of carbon adsorbent.

The pyrolysis product may be employed as a monolithic sorbent body inaccordance with the present invention, as is, but such pyrolysis productpreferably is activated in a manner producing a monolithic carbonsorbent product with ultramicroporosity having a high proportion, e.g.,at least 30% of porosity, preferably at least 50% of porosity, morepreferably at least 60% of porosity, and most preferably at least 70% ofporosity, such as 70 to 80% of porosity, of slit-shaped pores having asize in a range of from about 0.3 to about 0.72 nanometer and asignificant porosity, e.g., at least 20%, preferably at least 30%, morepreferably at least 50%, and most preferably at least 80%, e.g., 80 to90%, of the overall porosity comprising micropores, with diameter<2nanometers. The activation process can include any suitable processingsteps for enhancing the sorptive affinity of the material for thesorbate gas of interest or otherwise improving the characteristics ofthe sorbent medium for adsorption/desorption duty. For example, theactivation process can include heating in a non-oxidizing atmosphere,e.g., of nitrogen, argon, helium or other non-oxidizing gas, followed byswitching of the atmosphere to an oxidizing atmosphere, such as carbondioxide or steam for a brief duration, before switching to anon-oxidizing atmosphere and cooling to ambient temperature (e.g., roomtemperature). The specifics of the activation process, e.g., thetemperature levels and duration of the successive steps can be readilydetermined within the skill of the art without undue experimentation, bysimple variation of respective process conditions and analyticdetermination of the resulting sorbent performance, such as filldensity, porosimetry characterization, etc.

FIG. 1 is a graph of weight in grams of phosphine (PH₃) adsorbed perliter of carbon, as a function of pressure level, in torr, for a Kureha578-66-6 bead activated carbon (data points marked by solid diamondmarkers), a Takachiho ABF 14-03 particulate activated carbon (TakachihoKabushiku Kogyo, Ltd., Tokyo, Japan) (data points marked by solid squaremarkers), and monolithic carbon formed from polyvinylidene chloridepolymer (Saran A, Dow Chemical Co.) (data points marked by opentriangular markers).

The data in FIG. 1 show that the monolithic carbon formed from PVDCpolymer has a substantially higher weight of adsorbed phosphine perliter of carbon than either of the bead activated carbon adsorbent orthe Takachiho particulate activated carbon adsorbent, being generallymore than twice the sorptive loading of phosphine over the pressurerange of from 0 torr to 750 torr.

FIG. 2 is a graph of volume, in cubic centimeters, of arsine (AsH₃)adsorbed per liter of carbon, as a function of pressure level, in torr,for a Kureha 578-66-6 bead activated carbon (data points marked by soliddiamond markers) and carbon formed from polyvinylidene chloride polymer(Saran A, Dow Chemical Co.) (data points marked by open triangularmarkers).

FIG. 2 evidences the superiority of the monolithic carbon adsorbent overbead activated carbon for arsine loading. The volumetric loading ofarsine, in cubic centimeters, per liter of carbon is 50-100%+higher forthe monolithic carbon adsorbent over the pressure range of 0 torr to 770torr.

Set out below in Table 1 are fill density values of arsine on the threetypes of adsorbent materials discussed above in connection with FIG. 1,including Kureha 578-66-6 bead activated carbon, Takachiho ABF 14-03particulate activated carbon, and PVDC char monolithic adsorbent. Eachof the materials was evaluated for two samples at an arsine pressure of650 torr. Fill density was determined on a weight basis, as grams ofadsorbed arsine per gram of adsorbent, as well as on a volumetric basis,as grams of adsorbed arsine per liter of adsorbent.

TABLE 1 Arsine Capacity on Non-Monolithic Activated Carbon andMonolithic Carbon Fill Density at Fill Density at 650 Torr Pressure 650Torr Pressure (grams arsine/gram (grams arsine/ Adsorbent of adsorbent)liter of adsorbent) Kureha 578-66-6 (sample 1) 0.51 301 Kureha 578-66-6(sample 2) 0.51 301 Takachiho ABF 14-03 0.55 319 (sample 1) TakachihoABF 14-03 0.55 319 (sample 2) PVDC char (sample 1) 0.43 486 PVDC char(sample 2) 0.45 504

The results in Table 1 show that while the fill density on a weightbasis for the monolithic carbon adsorbent was approximately 15-20% lowerthan for the non-monolithic activated carbon adsorbents, the filldensity of the monolithic carbon adsorbent on a volumetric basis waswell over 50% higher than the corresponding fill densities of thenon-monolithic activated carbon adsorbents.

Table 2 below is a corresponding fill density tabulation for filldensity values of phosphine on the three types of adsorbent materialsdiscussed above in connection with FIG. 1, including Kureha 578-66-6bead activated carbon, Takachiho ABF 14-03 particulate activated carbon,and PVDC char monolithic adsorbent.

TABLE 2 Phosphine Capacity on Non-Monolithic Activated Carbon andMonolithic Carbon Fill Density at Fill Density at 650 Torr Pressure 650Torr Pressure (grams phosphine/ (grams phosphine/ Adsorbent gram ofadsorbent) liter of adsorbent) Kureha 578-66-6 0.165 97.4 Takachiho ABF14-03 0.184 107 PVDC char 0.188 212

The results in Table 2 show that the monolithic carbon adsorbent (PVDCchar) had a fill density on both weight and volumetric basis that wasabove those of the non-monolithic forms of activated carbon adsorbent,with the fill density on a volumetric basis being on the order of 100%higher than the volumetric fill density of phosphine on thenon-monolithic forms of activated carbon.

The sorbate fluid retained on the monolithic carbon adsorbent in thebroad practice of the present invention can be of any suitable type,including for example, hydride gases (such as arsine, phosphine,germane, silane, mono-, di-, and tri-substituted silanes, e.g., alkylsilanes of such types), halide gases (such as boron trifluoride, borontrichloride, halogen-substituted silanes, etc.) and gaseousorganometallic compositions.

Illustrative sorbate gas species that are usefully storable anddispensable in the practice of the invention include silane, germane,arsine, phosphine, phosgene, diborane, germane, ammonia, stibine,hydrogen sulfide, hydrogen selenide, hydrogen telluride, nitrous oxide,hydrogen cyanide, ethylene oxide, the deuterated hydrides, halide(chlorine, bromine, fluorine, and iodine) compounds, including suchcompounds as F₂, SiF₄, Cl₂, ClF₃, GeF₄, SiF₄, boron halides, etc., andorganometallic compounds of metals such as aluminum, barium, strontium,gallium, indium, tungsten, antimony, silver, gold, palladium,gadolinium, etc.

The pressure at which the sorbate gas is stored in the vessel may be anysuitable pressure appropriate to the application for which the gasstorage and dispensing system of the invention is employed. Illustrativepressure levels generally useful in the practice of the inventioninclude pressures not exceeding about 2500 torr, more preferably notexceeding 2000 torr, e.g., a pressure in a range of from about 20 torrto about 1800 torr, or more restrictively from about 20 torr to about1200 torr. For applications such as ion implantation, the pressure ofthe gas in the gas storage and dispensing vessel typically does notexceed about 800 torr, and the stored gas may be at subatmosphericpressure, e.g., a pressure in a range of from about 20 torr to about 750torr.

FIG. 3 is a schematic representation of a storage and delivery systemaccording to one embodiment of the invention.

As shown, the storage and dispensing system 200 comprises a storage anddispensing vessel 204 that is joined at its upper portion to a valvehead 206 comprising part of a dispensing assembly including manualactuator 208 for the valve head on the cylinder. The vessel may beformed of any suitable material of construction, e.g., comprisingmaterial such as metals, glasses, ceramics, vitreous materials,polymers, and composite materials. Illustrative metals for such purposeinclude steel, stainless steel, aluminum, copper, brass, bronze, andalloys thereof. The valve head is joined by means of coupling 210 to adispensing conduit 212 having disposed therein a pressure transducer214, an inert purge unit 216 for purging the dispensing assembly withinert gas, a mass flow controller 220 for maintaining constant flow ratethrough the dispensing conduit 212 during the dispensing operation, anda filter 222 for removing particulates from the dispensed gas prior toits discharge from the dispensing assembly.

The dispensing assembly further comprises a coupling 224, for matablyengaging the dispensing assembly with downstream piping, valving, orother structure associated with the locus of use of the desorbed fluid,e.g., involving a semiconductor manufacturing facility such as an ionimplantation tool using the dispensed gas as an implant species.

The fluid storage and dispensing vessel 204 is shown partially brokenaway to show the interior monolithic sorbent body 205.

FIG. 4 is a perspective view of a fluid storage and dispensing apparatusemploying a rectangular parallelepiped fluid storage and dispensingvessel 310 according to another and preferred aspect of the presentinvention. The rectangular parallelepiped fluid storage and dispensingvessel 310 is equipped with a pipe valve connection valve head 312 andhandles 314 welded to the top face of the vessel. The vessel 310 in aspecific embodiment is formed with a welded steel wall construction,having a square cross-section along the vertical (longitudinal) axis ofthe vessel. The walls of the vessel are 0.100 inch thick carbon steel,and the interior volume of the vessel is 3.62 liters. The handles 314are ¼ inch rod stock, formed into the shape shown, and welded at therespective ends to the vessel 310.

The dispensing valve of the pipe valve connection valve head 312 isthreadably engaged with the vessel 310, by a 1½″ pipe thread connection.The valve head may have any suitable number of ports, e.g., single portvalve heads, dual port valve heads, 3-port valve heads, etc.

The rectangular parallelepiped fluid storage and dispensing vessel 310contains a monolithic carbon adsorbent in its interior volume, whereinthe monolithic mass may include one or alternatively multiple monolithiccarbon bodies, each preferably of a rectangular parallelepiped shape toconform to the shape of the interior volume of the vessel, as previouslydescribed.

FIG. 6 is an elevation view, in partial section, of a fluid storage anddispensing system 400 utilizing a monolithic sorbent, according to afurther embodiment of the invention.

The system 400 includes a cylindrical fluid storage and dispensingvessel 401 having sidewall 402 and floor 403 enclosing an interiorvolume containing disk-shaped monolithic sorbent articles 410, 412, 414,416, 418, 420, 422, 424, 426, 428, 430 and 432, stacked in face-to-facerelationship to form the vertically extended composite body of sorbentarticles within the vessel.

The floor 403 of the vessel 401 is as shown in FIG. 6 of a concave form,with an outer annular portion 404 serving to enclose an interior annularplenum volume that is devoid of sorbent material, and which therebydefines an interior annular space that is in communication with thespace between the sidewall 402 and the adjacent stack of disk-shapedarticles. The interior annular plenum volume thus permits disengaged(desorbed from the sorbent) or otherwise free gas to flow upwardly alongthe inner surface of the sidewall, for ultimate dispensing from thevessel.

In the vessel 401, the respective disk-shaped monolithic sorbentarticles 410, 412, 414, 416, 418, 420, 422, 424, 426, 428, 430 and 432may each be of a same diameter and thickness, with the exception thatthe uppermost monolithic sorbent article 432 has a central passage 434therein, to accommodate the filter 440.

At its top portion, the upper edges of the sidewall 402 are secured to aneck collar 408, e.g., by welding, brazing, or other suitable securementtechnique or structure. The neck collar 408 has a central opening 442therein, communicating with central passage 434 of the uppermostmonolithic sorbent article 432, and the central opening 442 has athreaded interior surface 444, with which the complementary threading ofvalve head 460 can be threadably engaged.

The valve head 460 includes a main valve body having a valve structuretherein (not shown) with a threaded lower portion for engagement withthe threaded interior surface 444 of the central opening 442 in aleak-tight manner, and the valve head has interior passage(s) thereincommunicating with the dispense port 462, which may include a fittingthreadably engaged with a passage opening in the valve head, for joiningto external flow circuitry, to enable gas dispensing from the system400. The valve head interior passage(s) also communicate with an inletport of the valve head, in which is disposed the bushing 452 to which isjoined feed tube 450 having filter 440 joined to its lower end.

By this arrangement, gas desorbed from the sorbent in the vessel 401 isflowed in the dispensing operation to the central passageway 434, entersthe filter 440, flows through feed tube 450 and a central opening in thebushing 452, into the interior passage(s) of the valve head 460. Theinterior passage(s) of the valve head may be suitably formed toaccommodate interaction with a stem assembly and valve element (notshown) that is translatable between a fully open and a fully closedposition of the valve in the valve structure within the valve head 460.The stem assembly in turn is coupled with a valve actuator 464, which inthe embodiment shown is a hand-wheel for manual opening and closing ofthe valve, but which alternatively may comprise an automatic actuator,such as a solenoid actuator, pneumatic actuator, or the like, coupled tosuitable actuating circuitry, power supplies, central processor units,etc.

The neck collar 408 at its upper neck portion has an exterior necksurface that is threaded to matably engage a cap 466 that iscomplementarily threaded on the lower interior surface of the cap. Thecap has ventilation openings 468 therein, to allow venting of theinterior volume of the cap that is secured to the neck collar 408 of thevessel 401. The cap serves to protect the valve head 460 from impact andenvironmental exposure, and is readily unscrewed from the neck collar408 to access the valve head for coupling to gas flow circuitry for thedispensing of gas in the dispensing mode of the system 400.

The dispensing of gas from the vessel 401 may be carried out in anyappropriate mode of operation. For example, the valve head 460 may becoupled with gas flow circuitry to a semiconductor process tool or othergas-utilizing apparatus or site, with gas being desorbed under theimpetus of a reduced pressure in the flow circuitry external of thevessel. Additionally, or alternatively, the vessel may be subjected toheating, e.g., by the installation of a heating jacket about the vessel,whereby the sorbent is heated to desorb gas therefrom for dispensing. Asa still further alternative or additional mode of dispensing, anextraction system, e.g., an extraction pump, eductor, venturi,compressor, turbine, or other device effective to withdraw gas from thevessel, may be employed.

By providing the sorbent medium in the form of monolithic disk-shapedarticles in a stacked array as shown in FIG. 6, there is provided ahighly compact arrangement in which substantially the full interiorvolume of the vessel 401, e.g., other than the interior annular space atthe lower periphery of the interior volume of the vessel, and thecentral passage 434 of the uppermost monolithic sorbent article 432, isfilled with sorbent. The monolithic sorbent articles can be made of adiameter that is closely proximate to the inner diameter of the vessel,so that there is a minimal clearance between the side edges of themonolithic sorbent articles and the interior sidewall surface of thevessel adjacent thereto, as sufficient to accommodate flow of gas fromthe sorbent along the sidewall to the upper portion of the vessel fordispensing.

The sorbent in the interior volume of the vessel of FIG. 6 may beprovided, as in the illustrated arrangement, by a stack of disk-shapedmonolithic articles of sorbent material, or alternatively in othermanner. For example, the sorbent may be provided as a unitarycylindrical monolithic article that is installed in the vessel prior tothe securement of the neck collar to the upper edges of the sidewall402. As another alternative, the sorbent may be formed in situ in thevessel interior volume, as described hereinabove.

FIG. 7 is an elevational view, in cross-section, of the top and bottomportions of the cylindrical fluid storage and dispensing vessel of FIG.6, showing the details of the neck collar 408 and the lower extremity ofthe vessel 401.

As shown in FIG. 7, the neck collar 408 is secured to the upper edge ofthe sidewall 402 of the vessel 401. As mentioned, the neck collar may besecured to the sidewall in any suitable manner, but in general it ispreferred to weld the neck collar to the sidewall at its upper end. Thevessel 401 has a longitudinal axis L-L, as shown in FIG. 7, along whichthe monolithic sorbent articles are coaxially aligned with one anotherin the interior volume 409 of the vessel.

The neck collar 408 has an upper boss section circumscribing the centralopening 442 having threaded interior surface 444 to accommodateengagement with the valve head. The upper boss section has a drainpassage 411 therein, to allow condensate or other liquid to drain fromthe neck collar, and thereby minimize the potential for corrosion orother adverse effect associated with the presence of moisture or otherliquid.

By way of example, in one specific embodiment of the system 400 shown inFIGS. 6 and 7, and with reference to the dimensional characteristicsillustrated in such drawings, the fluid storage and dispensing systemmay have an overall height A of 19.5 inches, a height B measured fromthe base of the vessel to the centerline of the dispense port 462 of14.69 inches, a sidewall height C of 12.74 inches, a height D measuredfrom the base of the vessel to the drain passage 411 of 13.25 inches, aheight E measured from the lower face of the neck collar 408 to the topsurface of the upper boss section of the neck collar, of 1.275 inches, avessel diameter F of 4.25 inches, and a sidewall minimum thickness t of0.085 inch, within ASTM A568 thickness tolerance, with the sorbentarticles each having a diameter of 3 15/16 inches and a thickness,measured along the central axis L-L of the vessel, of 1 inch. The cap insuch embodiment has a height of 6½ inches, and is formed of stainlesssteel or carbon steel of suitable character. The vessel is formed of ahot rolled sheet, continuous cast, drawing steel, aluminum killed inaccordance with ASTM A1011/A1011M-04a (DS Type A modified).

It will be appreciated that the compositions and methods of theinvention may be practiced in a widely variant manner, consistent withthe broad disclosure herein. Accordingly, while the invention has beendescribed herein with reference to specific features, aspects, andembodiments, it will be recognized that the invention is not thuslimited, but is susceptible of implementation in other variations,modifications and embodiments. Accordingly, the invention is intended tobe broadly construed to encompass all such other variations,modifications and embodiments, as being within the scope of theinvention hereinafter claimed.

1. A method of supplying fluid for use in a semiconductor manufacturingprocess, said method comprising desorbing the fluid from a monolithiccarbon adsorbent on which the fluid has previously been adsorbed, andflowing the desorbed fluid to the semiconductor manufacturing processfor use therein, wherein the monolithic carbon adsorbent has a bulkdensity of from 0.9 to 2.0 g/cm³, a fill density measured for arsine gasat 25° C. and pressure of 650 torr that is greater than 400 g arsine perliter of adsorbent, and porosity at least 20% of which comprises poresof diameter below 2 nm.
 2. The method of claim 1, wherein the previouslyadsorbed fluid is stored on said monolithic carbon adsorbent prior tothe desorbing, at pressure in a range of from 20 to 1800 torr.
 3. Themethod of claim 1, wherein the previously adsorbed fluid is stored onsaid monolithic carbon adsorbent prior to the desorbing, at pressure ina range of from 20 to 1200 torr.
 4. The method of claim 1, wherein thepreviously adsorbed fluid is stored on said monolithic carbon adsorbentprior to the desorbing, at subatmospheric pressure.
 5. The method ofclaim 1, wherein the fluid is filtered to remove particulates therefromprior to use in the semiconductor manufacturing process.
 6. The methodof claim 1, wherein the fluid comprises a fluid species selected fromthe group consisting of hydrides, arsine, phosphine, germane, silane,mono-, di-, and tri-substituted silanes, alkyl silanes of such types,halides, boron trifluoride, boron trichloride, halogen-substitutedsilanes, organometallic gases, phosgene, diborane, ammonia, stibine,hydrogen sulfide, hydrogen selenide, hydrogen telluride, nitrous oxide,hydrogen cyanide, ethylene oxide, deuterated hydrides, halide (chlorine,bromine, fluorine, and iodine) compounds, F2, SiF4, Cl2, ClF3, GeF4,SiF4, boron halides, organoaluminum compounds, organobarium compounds,organostrontium compounds, organogallium compounds, organoindiumcompounds, organotungsten compounds, organoantimony compounds,organosilver compounds, organogold compounds, organopalladium compounds,and organogadolinium compounds.
 7. The method of claim 1, wherein thesemiconductor manufacturing process comprises ion implantation.
 8. Themethod of claim 7, wherein the fluid comprises an implant species. 9.The method of claim 1, wherein the monolithic carbon adsorbent has abulk density in a range of from 1 to 1.3 g/cm³.
 10. The method of claim1, wherein the monolithic carbon adsorbent has a bulk density in a rangeof from 1.05 to 1.25 g/cm³.
 11. The method of claim 1, wherein themonolithic carbon adsorbent is a pyrolyzate of a PVDC-based polymer. 12.The method of claim 1, wherein the monolithic carbon adsorbent comprisesa plurality of adsorbent articles each of whose x, y, and z axisdimensions is greater than 1.5 cm.
 13. The method of claim 1, whereinthe monolithic carbon adsorbent comprises a plurality of adsorbentarticles each of whose x, y, and z axis dimensions is greater than 2 cm.14. The method of claim 12, wherein said plurality of adsorbent articlescomprises disc-shaped adsorbent articles.
 15. The method of claim 1,wherein the monolithic carbon adsorbent has a fill density measured forarsine gas at 25° C. and pressure of 650 torr that is greater than 450 garsine per liter of adsorbent.
 16. The method of claim 1, wherein atleast 30% of the porosity of the monolithic carbon adsorbent comprisespores having a size in a range of from 0.3 to 0.72 nm.
 17. The method ofclaim 1, wherein the fluid is desorbed from the monolithic carbonadsorbent under the impetus of a reduced pressure in a path for saidflowing of the desorbed fluid to the semiconductor manufacturingprocess.
 18. The method of claim 17, wherein the desorbed fluid isflowed through a mass flow controller in said path.
 19. The method ofclaim 1, wherein the monolithic carbon adsorbent comprises a pluralityof disk-shaped adsorbent articles in a vertically extending stackedarrangement.
 20. A method of supplying fluid for use in an ion implanterin a semiconductor manufacturing process, said method comprisingdesorbing the fluid from a monolithic carbon adsorbent on which thefluid has previously been adsorbed, and flowing the desorbed fluid tothe ion implanter in the semiconductor manufacturing process for usetherein, wherein the monolithic carbon adsorbent has a bulk density offrom 0.9 to 2.0 g/cm³, a fill density measured for arsine gas at 25° C.and pressure of 650 torr that is greater than 400 g arsine per liter ofadsorbent, and porosity at least 20% of which comprises pores ofdiameter below 2, and the fluid comprises a fluid species selected fromthe group consisting of arsine, phosphine, and boron trifluoride.